FAYETTEVILLE (AP) — A federal judge has ordered an Arkansas man charged with mailing threatening letters and nontoxic white powder to be held in custody until his upcoming trial.

Philip Hanson sought his release in a detention hearing Thursday. But after hearing testimony and reviewing evidence, a judge ordered Hanson held until his trial, which is scheduled for July 9 in Fayetteville.

Hanson has pleaded not guilty to charges of mailing threatening communications. Authorities say he sent threatening letters and white powder to some of his former co-workers at a Christian greeting card company.

No one was injured by the nontoxic powder, some of which was identified as baking soda, but its arrival prompted several evacuations last year.

That scare in northwest Arkansas came about a decade after a number of envelopes containing a white powder that turned out to be anthrax were mailed to news organizations and other locations.

Hanson’s attorney, Ken Osborne, said Friday that Hanson is innocent, but he declined to comment further.

A number of employees at DaySpring and elsewhere received letters last fall, along with white power, an FBI agent wrote in a complaint filed in federal court.

“Make sure you have a will made out and it is updated,” one letter read. “You might want to upgrade your security at work and home.”

Hanson lost his job at DaySpring in 2009 after he had worked there for nearly three decades.